This fun little addon does two things:

First, it adds lots of new emotes to the game; /grats now works in exactly the same way as /congratulations (why didn't it before? Well, it does now), and you have some other fun ones created using the /me emote, like /envy, /sulk, /frustrated, and so on. Tons of preset ones already. Lots of fun, and great for RP.

Secondly, it's even useful because it can alias any command you can type to a shorter one (for example, /gm brings up the GM help pane using a longer /script commnd, which is really useful if your UI hides those icons for more screen space like mine does).

(Note: Emotes created using /me (such as the ones in the Emotomania_CustomEmotes table) do not work cross-faction, due to a deliberate game mechanic imposed by Blizzard to prevent free cross-faction communication. No matter what you put, the other faction will simply see "<Name> makes some strange gestures." - so stick to built-in emotes, like /hug and /charge, or /spit if you really must, you disgusting person you, to express your intentions towards the other faction.)

You can add your own custom emotes, and command aliases, by simply editing the Emotomania.lua file - the table's near the top of the file and it's pretty easy to edit - you should get the hang of it pretty quick.